Controversy has broken out over the Pope's planned open-air Mass at Bellahouston Park, near Glasgow, with many parishes returning more than half of their allocated tickets for the event.

The organisers now reportedly fear that attendance will fall short of the 100,000 they expected to come to the Mass, which will cost £1.5m to stage. Each of Scotland's 450 Catholic parishes received a pro-rata ticket allocation based on the size of its regular congregation, but the Herald reports that, in some cases, only one-sixth of the parishioners are planning to take up their places at the papal event.

In 1982, Pope John Paul II celebrated Mass at the same site on a sunny afternoon, with 300,000 people in attendance. The choice of this site has been interpreted as an attempt to re-create the success and popularity of that service for a pope who has been under siege in recent months.

The open-air Mass requires participants to be in their places hours before the two-hour service begins, and it is thought that fears about the weather and long travel times are putting people off. Distant parishes are also planning to watch the service via video link, rather than travel to the other side of the country to attend in person.

The service, which will take place on 19 September during the Pope's state visit to Britain, has also reopened the debate over the cost of the papal trip to Britain. Although it insists that pilgrims will not have to pay to attend the Mass at Bellahouston, the Catholic Church has asked each parish to make a donation of £20 per attendee -- an obligation that many parishes have passed on to their parishioners.

The total cost of the visit, which will be borne by Britain, as the host nation, provoked outrage in some quarters when it was revealed that it could exceed £20m. As well as asking for "voluntary donations" from the public to cover the cost of specific events, the Catholic Church is also asking members to donate towards the overall cost of the visit, which it currently estimates at £7m.

The Church is also selling merchandise to coincide with the trip. T-shirts, fridge magnets and mugs are available, as well as more conventional religious artefacts.

Besides being hit by low attendance figures, the Pope's visit could suffer from a lack of television exposure, after BBC workers threatened to strike during that period (which will coincide with other major events such as the Last Night of the Proms) over pension disputes. Workers are being balloted on the issue; a result is expected in the week before the Pope is due to arrive in Britain.

Add to this the stated intention of Richard Dawkins and others to attempt to arrest the Pope for his alleged complicity in the child abuse scandal while he is on British soil, and we could be in for an eventful visit come September.